1. Field of the Invention
This invention relates to the adjustment of the length of an oil well tubular completion string, especially where an electrical component, such as an electric submersible pump, is employed as a component in a tubing string.
2. DESCRIPTION OF THE PRIOR ART
Where an electric submersible pump is employed on the bottom of a tubing string in an oil well, it is necessary to extend an electrical cable from the surface of the well to the submersible pump. This requires the cable to be attached to a conventional packer, or other means such as a bridge plug, for isolating the tubing casing annulus thereabove from that below and from the production zone, engaging both the tubing string and the outer oil well casing at some point between the surface of the well and the submersible pump as the electrical cable must pass through the packer.
One of the problems encountered in the use of electric submersible pumps is that the pump will vibrate during operation and this vibration can cause the electrical cable, due to the amount of slack in the cable, to prematurely fail. By removing any slack in the electric cable between the location of the packer and the electric pump, the operating life of the cable and, therefore, the entire submersible pump tubing string can be extended. One means of removing the slack in the cable extending between the packer and the submersible pump is to employ some means to space out or stretch out the tubing extending between the packer and the pump. Conventional spacing elements generally require rotation in order to lengthen, or shorten, the tubing string between integral components in an oil well completion. Since the electric cable is carried on the exterior of the tubing string, these conventional rotational spacers would not provide an effective means of elongating the tubing string between a packer and a pump.